21201554 has 8 divisors (see below), whose sum is σ = 34693488. Its totient is φ = 9637060.

The previous prime is 21201553. The next prime is 21201563. The reversal of 21201554 is 45510212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21201553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 481832 + ... + 481875.

It is an arithmetic number, because the mean of its divisors is an integer number (4336686).

Almost surely, 2^21201554 is an apocalyptic number.

21201554 is a deficient number, since it is larger than the sum of its proper divisors (13491934).

21201554 is a wasteful number, since it uses less digits than its factorization.

21201554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 963720.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 21201554 is about 4604.5145238125. The cubic root of 21201554 is about 276.7722630415.

Adding to 21201554 its reverse (45510212), we get a palindrome (66711766).

The spelling of 21201554 in words is "twenty-one million, two hundred one thousand, five hundred fifty-four".